Current switching circuits selectively enable current flow in response to a control signal voltage. Some circuits, for example digital-to-analog converters and voltage controlled oscillators, require highly accurate current switching circuits for their input. A number of different current switching circuits are known, both for field-effect and for bipolar transistor implementations. Those which are designed for field-effect transistor implementation typically have their switching speed limited by the time constants of various internal nodes due to the required charging time for parasitic capacitances. Moreover, these time constants are likely to change significantly with process variations from one wafer to the next in manufacture, thus making it difficult to control the operating parameters of the circuit. Another problem with field-effect transistor circuits is the coupling of switching transients to the output through parasitic capacitances of the transistors. Efforts to avoid these shortcomings usually involve the provision of additional devices in a cascode configuration to provide some isolation from the undesired effects. However, such measures make the resulting circuits more complex and costly.